Hello all, I am new here, and came to see if you guys could help me out with a little problem I'm having.

I have a 1997 F-150 with the 4.6L and I have replaced my thermostat, and water pump yesterday, but it still blows cold air and heats up, and heat works when it wants too. Temp gauge goes up to red and then I usually get heat and it goes back down pretty fast, I don't know what to do.

 

Radiator could be plugged.

 

u might need to purge it,u might have air in the system.can u actually see the truck over heating,perhaps a bad temp.sensor.(just a thought)

 

I took it to where i got from, and they're fixing it for me.